1. Field of Industrial Usefulness
This invention relates to a fastening method of a casing etc. having a pair of casing members. As a casing to which the present invention is applicable, there are a casing for a double diaphragm type actator, a casing for a brake booster, various casings such as a pump casing etc., and various containers similar to a casing.
2. Prior Art
There have conventionally been many methods for fastening opening ends of a pair of casing members. For example, there have been a bolt fastening method, a swage fastening method, and a method for fastening stoppers by pressing and twisting a flange of a casing member against another.
In the bolt fastening method or the fastening method utilizing the twisting, however, many manhours are required for assembly work. While, a strength (fastening force) of a fastened portion is questionable in the swage fastening method.